/*_############################################################################
  _## 
  _##  SNMP4J 2 - DefaultThreadFactory.java  
  _## 
  _##  Copyright (C) 2003-2011  Frank Fock and Jochen Katz (SNMP4J.org)
  _##  
  _##  Licensed under the Apache License, Version 2.0 (the "License");
  _##  you may not use this file except in compliance with the License.
  _##  You may obtain a copy of the License at
  _##  
  _##      http://www.apache.org/licenses/LICENSE-2.0
  _##  
  _##  Unless required by applicable law or agreed to in writing, software
  _##  distributed under the License is distributed on an "AS IS" BASIS,
  _##  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  _##  See the License for the specific language governing permissions and
  _##  limitations under the License.
  _##  
  _##########################################################################*/
package org.snmp4j.util;

import org.snmp4j.util.*;
import org.snmp4j.SNMP4JSettings;

/**
 * The <code>DefaultThreadFactory</code> creates {@link WorkerTask} instances
 * that allow concurrent execution of tasks. By default it uses a timeout
 * of 60 seconds (1 min.) when joining threads on behalf of an call of the
 * {@link WorkerTask#join()} method. By setting
 *
 * @author Frank Fock
 * @version 1.10.2
 * @since 1.8
 */
public class DefaultThreadFactory implements ThreadFactory {

    private long joinTimeout;

    public DefaultThreadFactory() {
        joinTimeout = SNMP4JSettings.getThreadJoinTimeout();
    }

    /**
     * Creates a new thread of execution for the supplied task.
     *
     * @param name the name of the execution thread.
     * @param task the task to be executed in the new thread.
     * @return the <code>WorkerTask</code> wrapper to control start and
     *   termination of the thread.
     */
    public WorkerTask createWorkerThread(String name, WorkerTask task, boolean daemon) {
        WorkerThread wt = new WorkerThread(name, task);
        wt.thread.setDaemon(daemon);
        return wt;
    }

    /**
     * Sets the maximum time to wait when joining a worker task thread.
     * @param millis
     *    the time to wait. 0 waits forever.
     * @since 1.10.2
     */
    public void setThreadJoinTimeout(long millis) {
        this.joinTimeout = millis;
    }

    public class WorkerThread implements WorkerTask {

        private Thread thread;
        private WorkerTask task;
        private boolean started = false;

        public WorkerThread(String name, WorkerTask task) {
            this.thread = new Thread(task, name);
            this.task = task;
        }

        public void terminate() {
            task.terminate();
        }

        public void join() throws InterruptedException {
            task.join();
            thread.join(joinTimeout);
        }

        public void run() {
            if (!started) {
                started = true;
                thread.start();
            } else {
                thread.run();
            }
        }

        public void interrupt() {
            task.interrupt();
            thread.interrupt();
        }
    }
}
